Just outside the western gate is the ‘teak forest’ temple of Wat Pa Sak. Several structures are still visible. The main chedi (pagoda) was built in 1340 by Saen Phu, the founder of Chiang Saen. The temple’s name alludes to the hundreds of teak trees planted on the order of Saen Phu.
Wat Pa Sak, ‘The Teak Forest Monastery’ owes its name to the teak trees which still stand along the perimeter of Chiang Saen’s city walls, which are located just a few hundred meters from this monastery. Its principle item of interest is a brick and stucco chedi dating from around 1319 (some chronicles indicate 1295, but that is unlikely since it is earlier than the founding of Chiang Saen). The chedi enshrines a relic from Pataliputra in India. Stylistically, it is influenced by Mon design which favored stacked square tiers with standing Buddhas embedded in each tier. It also shows Sukhothai influence in the detail of stucco work that survives on one of the higher tiers.
Apart from the chedi, the ruins of an ubosot with several standing stone columns can be found in front of the chedi. There are also scattered stone foundations of indeterminate purpose in the fields surrounding the site.